Zero-flux fluxgate current sensor for AC-DC heavy-current measurement

Abstract

The invention discloses a zero-flux fluxgate current sensor for AC-DC heavy-current measurement. The sensor comprises a primary current line, a secondary current line, an annular magnetic core, a fluxgate measuring magnetic core unit, and a processing circuit. The primary current line passes through the center of the annular magnetic core to be connected with a current line to be measured. The secondary current line is wound around the annular magnetic core. The geometrical symmetry line of the annular magnetic core is provided with two symmetrical grooves. The fluxgate measuring magnetic core unit is fixed in the grooves of the annular magnetic core and is connected with the input end of the processing circuit. The primary current line passes through the center of the annular magnetic core and generates a primary magnetic flux. The fluxgate measuring magnetic core unit generates a voltage signal based on the induced magnetic flux, and the voltage signal outputs secondary current to the secondary current line via the processing circuit. The secondary current line generates a secondary magnetic flux on the annular magnetic core, wherein the secondary magnetic flux forms a dynamic balance with the primary magnetic flux. Based on the measurement result of the secondary current, a primary current value to be measured can be obtained.

Description

technical field [0001] The invention relates to the technical field of measuring electric variables, and more particularly relates to a zero-flux fluxgate current sensor for measuring AC and DC large currents. Background technique [0002] Current measurement is a technical discipline with a long history and continuous development for human beings to observe and use electrical phenomena. The coverage of current measurement is very wide, and there are different measurement methods for different current amplitudes and current change characteristics. Ordinary current sensors generally can only measure AC, while many fields such as basic science, applied scientific research, and applied technology need to detect, regulate, and control DC current. The traditional AC and DC detection method is generally the sampling resistor shunt detection method. The principle of this detection technology is simple, and it shows high precision and fast response speed in the current measurement ...

AI Technical Summary

Problems solved by technology

The traditional AC and DC detection method is generally the sampling resistor shunt detection method. The principle of this detection technology is simple, and it shows high precision and fast response speed in the low-frequency and small-amplitude current measurement. The measured current has no electrical isolation. In general, the measured current has a voltage of several hundred volts, and the measurement circuit is generally a few volts system. If the measurement circuit is not electrically isolated from the measured current, it is easy to damage the expensive measurement. loop system

Moreover, when measuring a large value of current from 100A to 1000A, the resistance shunt will generate a lot of heat, and the problem of temperature drift is inevitable. It is necessary to install a complex heat dissipation system to ensure the normal operation of the resistance shunt

Another AC / DC detection method is the closed-loop Hall current sensor detection method. Although the closed-loop Hall current sensor realizes the electrical isolation between the measurement circuit and the measured current, it also avoids the heating problem when measuring large-value currents from 100A to 1000A. However, due to the defects of the Hall device itself, it is easily affected by external environmental factors, and the accuracy level is difficult to make high, and the error is rarely less than 0.5%.

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